Fusion 4.1 support for pre-Lion, non-server OS X is a mistake, says VMware

Late on Friday, Macworld's Jason Snell discovered that the new 4.1 version of virtualization tool VMware Fusion had a special talent. Up until 4.1, Fusion would refuse to install non-server versions of Snow Leopard and Leopard into a virtual machine, since Apple's licensing for those OS builds did not include a virtualization option.

From TUAW:

It wasn't clear from the Fusion 4.1 release notes whether VMware had sought Apple's permission to make this adjustment to the install process, and I asked the Fusion team for comment. Earlier this evening, in a blog post, the company announced that the licensing check for Leopard Server and Snow Leopard Server (the only legitimately virtualizable versions of 10.5 or 10.6) was left out of the 4.1 build of Fusion. A subsequent update is likely to restore the checking routines that prevent the installation of non-server 10.5 and 10.6 OS versions.